Circuit breaker for low voltage alternating electric installation

ABSTRACT

The invention concerns a disconnecting appliance, such as a switch, a fuse-disconnecting switch or breaker-reversing switch, having a novel arrangement of fixed and moving contacts promoting contact surface self-cleaning and increasing contact force for the same contact force applied by the cam. Moreover, it comprises a newly designed cam for actuation the mobile contacts to optimize to the maximum the operating conditions when engaging and releasing. The appliance is characterized in that the moving contacts ( 35, 36 ) comprise two contact surfaces ( 38 ) arranged in substantially perpendicular planes, corresponding with those ( 27 ) of the fixed contacts ( 31, 31 ′ and  33, 33 ′), each moving contact ( 35, 36 ) moving in radial translation relative to the control shaft ( 23 ) along a direction (F) substantially perpendicular to a straight line passing through its two contact surfaces ( 38 ). The cam ( 50 ) comprises a flow track ( 56 ) and a return track ( 57 ), respectively corresponding to engaging and releasing, to guide a driving pin ( 45 ) integral with a moving element ( 40 ) coupled to the moving contacts, the moving element being arranged to be translated radially relative to the control shaft ( 23 ). The invention is applicable to any industrial electrical installation.

The present invention relates to an electrical disconnector for analternating low voltage electrical installation provided with at leasttwo phase conductors with or without a neutral conductor, comprising onedisconnecting module per conductor and one control module provided witha mechanism for operating said disconnecting modules, each disconnectingmodule comprising at least one input terminal connected to a fixedcontact, one output terminal connected to a fixed contact, another twofixed contacts connected to one another by a bridge or a fuse, formingwith the other fixed contacts two pairs of fixed contacts and two movingcontacts associated respectively with a pair of fixed contacts, anengaged position and a released position, the control module comprisingat least one control shaft coupled to an operating handle, this shaftcrossing said disconnecting modules and bearing at least one cam coupledto at least one translation moving element coupled to said movingcontacts to be moved from a first stable position called the engagedposition to a second stable position called the released position.

BACKGROUND OF THE INVENTION

These disconnectors, commonly called switches, fuses-switches orchange-over switches are designed to distribute energy to electricalinstallations or to control alternating low voltage industrialequipment, for example 380 V, and in a current range from a few dozen toa few thousand amps. So-called double disconnectors comprise two movingcontacts per pole or disconnecting module. More often than not, themoving contacts are made up of a rectilinear bar which performs aperfect translation movement between its two stable positions and thefixed contacts of a same pair are arranged in the same plane parallel tosaid moving contact. The translation movement of the moving contacts istraditionally obtained by a cam securely fixed at its center to thedisconnecting modules control shaft. The cam may have an almost ovalshape and comprise a guide path on its section. In this case, eachmoving contact is connected to a moving element provided on either sideof the control shaft and applied against the section of the oval cam bymeans of a spring. The rotation of the cam generated by the rotation ofthe control shaft drives the moving element in a radial translationmovement transmitted simultaneously to the corresponding moving contact.The virtually oval shape of the cam is generally optimized to allow asudden disconnection and an optimum operating force. The cam can also beround on which the moving elements are fixed at out-of-center points,thereby forming a rod-wheel system. In this way, the rotation of the camalso drives the radial translation of the moving element which istransmitted to the corresponding moving contact.

The known disconnectors described briefly above present numerousdrawbacks. Due to the fact that the moving contacts perform a perfecttranslation movement, there is no friction between the moving contactsand the fixed contacts when engaging and releasing takes place.Consequently, there is no self cleaning of the contact surfaces. This isdetrimental to the quality of the electrical contact. In particular, thecontact resistance increases with the number of operations performed andthe number of electric arcs established between the fixed and movingcontacts. The deterioration in the quality of electrical contact causesthe contact surfaces and the device in general to heat up, leading toJoule effect losses, as well as a reduction in the lifetime of both thecontacts and the device. Furthermore, in the standard devices, there isa relatively large number of parts. In particular, several intermediatecurrent-carrying parts have to be arranged to achieve the completecircuit from the input terminal to the output terminal. As these partsare frequently made of copper, the cost price of the disconnectingmodules remains relatively high. Furthermore, the force applied to themoving contact corresponds to that applied by the cam securely fixed tothe control shaft which is itself securely fixed to the operatinghandle. However, due to the fact that each rectilinear moving contactco-operates with two fixed contacts arranged in the same plane, theforce applied on each fixed contact corresponds to half the forcetransmitted by the cam. This implies increasing the operating force onthe handle to increase the force on the contacts, which is contrary tothe objective being sought when engaging. What is more, in standarddisconnecting devices, the speed and the distance the moving contactsmove according to the time are identical when engaging and releasing,which is detrimental to optimizing the physical conditions in either ofthe stable positions. Indeed, when engaging, the smallest possibleoperating force is sought, as well as the quickest possible engagingspeed. On the other hand, when releasing, a sudden disconnection issought to avoid electric arcs occurring as much as possible, as well asgood resistance to a force equal to three times the operating force,commonly called 3F and defined by an international standard.

Some publications describe electrical disconnecting devices designed tocreate friction between the fixed and moving contacts when engagingtakes place. This is notably the case in publications EP-A-252 285,EP-A-105 817 and CH-A-352 024. Nevertheless, none of them provides for aspecial layout of the contacts making it possible to increase thecontact force between them, nor different trajectories of the movingcontacts for the engaging and the releasing operations in order tooptimize the operating conditions.

In publication EP-A-252 285, it is a matter of a circuit breaker limitedto low currents (under 32 A) for domestic applications, which isprovided with a single disconnecting module and not an industrial switchprovided with several disconnecting modules. What is more, the contactsurfaces provided on the fixed contact and the moving contact arecoplanar. It is the mechanism for transmitting movement between thecircuit breaker's lever and the moving contact which generates afriction movement between the two contacts.

In publication EP-A-105 817, it is a question of a multistage switchlimited to currents from 25 to 32 A whose cam mechanism is only designedto ensure self-cleaning of the contacts by means of an auxiliary camwhich controls a carriage which moves the moving contacts by friction onthe fixed contacts. The contact surfaces provided on these fixed andmoving contacts are also coplanar.

In publication CH-A-352 024, it is a matter of a switch with two movingcontacts, whose contact surfaces are also coplanar, controlled by acentral rotating cam. The approach movement of the moving contacts isperformed according to an angle of 20 to 30° which, when contact ismade, leads to a pressure and self-cleaning friction on the contacts.

SUMMARY OF THE INVENTION

The aim of the present invention is to overcome these drawbacks byproposing a disconnector which presents a new layout of moving and fixedcontacts which favors the self cleaning of the contact surfaces andincreases the contact force for the same force applied by the cam. Whatis more, the disconnector proposed comprises a newly arranged cam makingit possible to meet the various characteristics required when engagingand releasing in order to optimize the operating conditions.

This aim is achieved for such a disconnector as defined in the preambleand characterized in that each moving contact comprises two contactsurfaces arranged in substantially perpendicular planes, in that thefixed contacts of the same pair are arranged in substantiallyperpendicular planes so that their respective contact surface is placedfacing the corresponding contact surface provided on said moving contactwhen it is in the engaged position and in that each moving contact movesin radial translation in relation to the control shaft in asubstantially perpendicular direction to a straight line passing by itstwo contact surfaces.

In a preferred form of embodiment, each moving contact comprises two endarms arranged on either side of a middle arm, forming an angle ofapproximately 45° in relation to said middle arm, the contact surfacesbeing provided on the two end arms.

The moving element is, advantageously, made up of a substantiallyrectangular frame extending at right angles through said disconnectingmodules and arranged in a substantially inclined plane parallel to thecontrol shaft.

The frame can comprise at least two parallel sides, oriented radially inrelation to the control shaft and arranged to slide along twocorresponding sides arranged in the enclosure of said device to guidesaid frame in translation.

In the preferred form of embodiment, for each corresponding movingcontact, the frame comprises a window oriented substantiallyperpendicular to the control shaft and a return spring housed in thiswindow to attract said moving contact in the direction of the fixedcontacts.

The frame also comprises at least one notch designed to receive saidcam, at least one side of this notch comprising a drive fingersubstantially parallel to the control shaft and engaged in at least onetrack provided in said cam.

Preferentially, the cam comprises, for each moving element, a noncircular recess, delimited by an inner wall close to the control shaftand an outer wall at a distance from the control shaft, these wallsbeing arranged to guide said drive finger, respectively when engagingand releasing.

The bottom of the recess advantageously comprises various reliefsarranged to define, respectively with the inner and outer walls, twodistinct tracks, i.e. an out track for engaging purposes and a returntrack for releasing purposes.

In the preferred form of embodiment, the out track comprises a firstpart which is substantially rectilinear and a second circular part witha small radius out-of-center in relation to the control shaft and thereturn track comprises a first circular part with a constant radiuscentered on the control shaft and a second circular part the radius ofwhich is smaller than said constant radius.

Advantageously, the second part of the out track communicates with thefirst part of the return track via a shoulder.

This cam advantageously comprises a central barrel rotating securelyfixed to the control shaft and sliding on the latter and the width ofthe notch provided in the moving element's frame is greater than that ofthe cam which allows it an axial clearance corresponding to thedifferences in relief at the bottom of the recess.

In the preferred embodiment, on at least one of its free ends, thebarrel has a cam profile co-operating with at least one lug provided atleast in the enclosure of said device and oriented radially in relationto the control shaft and the control shaft bears a return springarranged to keep the cam profile resting on said lug.

In an alternative embodiment, the recess can be extended, in a directionopposite to that of the out and return tracks, by a test track, framedby the inner and outer walls, this track being circular, close to thecontrol shaft, with a constant radius centered on this shaft.

In this alternative, the cam comprises on its rear side a circulargroove near the control shaft and centered on this shaft and the frameof the moving element comprises a guide shoe 46 arranged facing thedrive finger 45 and arranged to lodge itself in said groove when thedevice is in the test position.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and its advantages shall be more fully disclosedin the following description of an example of embodiment, given by wayof an unrestricted example with reference to the attached drawings, inwhich:

FIG. 1 shows a perspective of a disconnector according to the invention,with the covering cap withdrawn, the device being in the releasedposition,

FIG. 2 is a partial plan view, the main elements being shown in atransparent manner, the device being in the released position,

FIG. 3 is a partial perspective of the device in the released position,

FIG. 4 is a partial plan view, the main elements being shown in atransparent manner, the device being in the engaged position,

FIG. 5 is a partial perspective of the device in the engaged position,

FIG. 6 is a partial plan view, the main elements being shown in atransparent manner, the device being in the test position,

FIG. 7 is a partial perspective of the device in the test position,

FIG. 8 is a partial perspective showing the rear of the cam, and

FIG. 9 is a partial perspective showing details of the enclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, the disconnector 1 according to the inventioncomprises, in the example shown, one control module 2 and threedisconnecting modules 3. This device is designed for a three-phaseelectrical installation, i.e. provided with three phase conductors, butcould be adapted to any other installation. The disconnecting modules 3are either made up of independent, juxtaposed enclosures which areassembled using any known means, or grouped together in a singleenclosure 4. Each disconnecting module 3 is associated with a conductorfrom said installation and comprises in a known manner one inputterminal 30 connected to a fixed contact 31, one output terminal 32connected to a fixed contact 33, two other fixed contacts 31′, 33′ (notshown on this Figure) securely fixed to the device's covering cap,connected to one another by a current-carrying bridge 34 (not shown onthis Figure) or a fuse forming two pairs of fixed contacts, with theother fixed contacts 31, 33, as well as two moving contacts 35, 36 eachassociated with a pair of fixed contacts 31, 31′ and 33, 33′, having twostable positions, an engaged position and a released position. The fixedcontacts 31, 31′, 33, 33′ each comprise one contact surface made up of acontact piece 37 and the moving contacts 35, 36 each comprise twocontact surfaces made up of contact pieces 38 arranged to rest againstthe contact pieces 37 when the disconnector 1 is in the engagedposition. The moving contacts 35, 36 are mounted respectively in twoidentical, moving elements 40 arranged symmetrically in relation to theaxis A of said disconnector 1 and moving in translation according to twoopposite directions and substantially perpendicular to said axis A.

The control module 2 comprises in a known manner an enclosure 20, atransmission shaft 21 connected to an operating handle (not shown)accessible from outside said enclosure and coupled by means of toothedpinions 22, constituting a change of direction, to a control shaft 23for the moving contacts 35, 36, arranged in the axis A and crossing thedisconnecting modules 3. Nevertheless, the operating handle may becoupled directly to one of the ends of the control shaft 23 depending onthe configuration one wishes to give said disconnector. This arrangementis possible as, as shall be seen later on, the operating clearance issituated at the mechanism for controlling the disconnecting modules andno longer at the control module.

The control shaft 23 is securely fixed to each moving contact 35, 36 tocontrol them simultaneously in a synchronous and sudden manner. Thiscontrol module 2 also comprises a sudden action device 24 byaccumulation of energy, connected to said control shaft 23 and arrangedto bring about a quick engaging and releasing of the moving contacts inrelation to the fixed contacts. This sudden action device 24 makes itpossible in a known manner to avoid the stagnation of electric arcs whenreleasing, premature arc ignition when engaging and comprises a springmounted in such a way that all the intermediate positions between theengaged and released positions of the disconnector are unstable.

The control shaft 23 bears two identical cams 50 each mounted on abarrel 51 able to slide axially in relation to said shaft 23. These cams50 are pushed in the direction of the control module 2 by means of areturn spring 52 arranged on the control shaft 23 between one lateralside of the enclosure 4 and the closest barrel 51. Each cam 50 isdesigned to co-operate with the two moving elements 40 so as to move themoving contacts 35, 36 synchronously from their released position totheir engaged position and vice-versa.

FIGS. 2 to 7 partially illustrate the disconnector 1 by showing the mainparts which make up the present invention, in various positions. InFIGS. 2, 4 and 6, the parts are shown in a transparent manner, seen fromthe end of the control shaft 23. In FIGS. 3, 5 and 7, these parts areshown in perspective. The parts making up said disconnector 1 are almostall symmetrical in relation to the axis A.

The input terminals 30 and output terminals 32 are connectedrespectively to the fixed contacts 31 and 33. These fixed contacts 31,33 are each made up of a current-carrying bar bent at a right angle,with one of the arms being lodged in the corresponding terminal and theother arm bearing a contact piece 37 which is riveted for example. Theother two fixed contacts 31′, 33′ are made up of a current-carrying barbent twice at a right angle to form a step, with one of the arms beinglodged in the device's covering cap and the other arm bearing a contactpiece 37. The fixed contacts form two by two pairs of fixed contacts 31,31′ and 33, 33′, the contact pieces 37 of which are arranged inperpendicular planes. The fixed contacts 31′, 33′ are connected to oneanother either by means of a bridge forming a basic switch, or by meansof a fuse cartridge forming a fuse-switch.

The moving contacts 35, 36 are made up of a current-carrying barcomprising two end arms arranged on either side of a middle arm andforming with it a substantially 45° angle. Each end arm bears a contactpiece 38, which is riveted for example. The contact pieces 38 of thesame moving contact are arranged in perpendicular planes and aredesigned to be in contact with the contact pieces 37 of the pair ofcorresponding fixed contacts, in the engaged position. The movingcontacts 35, 36 are mounted respectively in the moving elements 40arranged to move them simultaneously, in a synchronous manner, intranslation in a direction F perpendicular to a straight line passingthrough the two contact pieces 38.

The bent or possibly rounded form of the moving contacts 35, 36 as wellas the 45° approach of the moving contacts in relation to the fixedcontacts make it possible to ensure self-cleaning of the contact pieces37, 38 for each engaging and releasing operation. Indeed, the contactpieces 38 are positioned on the contact pieces 37 or move away from themaccording to the translation movement F which is broken down into ahorizontal component F1 and a vertical component F2, each componentgenerating friction between the contact pieces 37, 38. Furthermore, theoperating force G transmitted to the moving contacts 35, 36 is passed onto the fixed contacts 31, 33 according to the horizontal component G1and on to the fixed contacts 31′, 33′ according to the verticalcomponent G2. As the angle of said operating force G is 45°, since it isparallel to the direction F, the value of the components G1 and G2 isequal to G/2, i.e. greater than G/2 as in the state of the technique.Therefore, for the same operating force, the contact force is increasedby 40%. This results in the electrical characteristics being improved:the breaking capacity and the short-circuit behavior are substantiallyimproved. Furthermore, the special construction of the fixed contactsand the moving contacts makes it possible to halve the total length ofcopper required, which leads to a reduction in the cost price of thewhole disconnector 1.

The moving elements 40 are each made up of a frame 41 which issubstantially rectangular and extends into the three disconnectingmodules and is arranged in an inclined plane passing through the controlshaft 23. This frame 41 comprises three rectangular windows 42, orientedradially in relation to the control shaft 23 and designed to receive themoving contacts 35, 36 of said modules. The width of the windows 42 isslightly bigger than that of the moving contacts 35, 36 so as to providesaid operating clearance mentioned previously. As a result, the frame 41floats slightly in relation to the rest of the mechanism. A returnspring 43 is provided in each window 42 to hold said moving contacts 35,36, in their flat middle arm, resting against said frame 41 orientedoutwards, i.e. away from the control shaft 23, in the direction of thefixed contacts. These springs 43 are centered in relation to theirwindow 42 by means of a notch (not visible) provided on the frame 41.This frame 41 also comprises two housings 44 which are also rectangular,designed to receive the two cams 50. On the sides facing each housing44, a drive finger 45 oriented parallel to the axis A and a guide shoe46 are provided respectively, each co-operating with the opposing sidesof the corresponding cam 50. The width of the housings 44 isapproximately equal to twice that of the cams 50, thereby allowing theman axial clearance D which shall be dealt with in detail later. Thisframe 41 is extended outwards by at least two transversal sides 47arranged to slide against corresponding transversal sides 48 provided inthe enclosure 4 of the disconnecting modules 3, so as to guide saidmoving element 40 in its translation movement. Each moving element 40 isthereby driven by its two fingers 45 guided in the two cams 50, so as toensure its radial translation movement parallel to the axis A.

Each cam 50 comprises a barrel 51 mounted slidingly on the control shaft23 corresponding to the axial clearance D mentioned above. The free endof this barrel 51 presents left cam profile 53 co-operating with twofacing lugs 54 provided respectively on the enclosure 4 (cf FIG. 9) andthe cap (not shown) of said device 1, on the control module 2 side. Thiscam profile 53 makes it possible on the one hand to mechanically coupletwo consecutive barrels 51 when two cams 50 are mounted on the controlshaft 23 and on the other hand allows the axial clearance D of saidcams, the purpose of which will be specified later. The return spring 52(cf FIG. 1) keeps this cam profile 53 resting on the lugs 54. The cams50 are arranged to simultaneously move the two moving elements 40,synchronously and in translation according to F, and for this purposethey comprise two non circular recesses 55 on the drive fingers 45 side,i.e. the distance of which up to the axis A varies according to theangle of rotation, these two recesses being identical and offset by anangle of 120°. The details which follow concern one single recess 55co-operating with the drive finger 45 of one single moving element 40associated with one single set of moving contacts 36.

This recess 55 is defined laterally by an inner wall 55 a close to theaxis A and an outer wall 55 b away from the axis A, the purpose of thesewalls being to guide the drive finger 45. The bottom of the recess 55comprises various reliefs defining, respectively with the inner wall 55a and external wall 55 b, two distinct tracks 56, 57, the purpose ofwhich is also to guide the drive finger 45: one out track 56 to guidethe finger 45 from the released position to the engaged position and onereturn track 57 to guide the finger 45 from the engaged position to thereleased position.

The way the cam 50 associated with the drive finger 45 operates isdetailed with reference to FIGS. 2 and 3 showing the released positionand FIGS. 4 and 5 showing the engaged position.

When the engaging operation takes place, i.e. to go from the releasedposition (cf FIGS. 2 and 3) to the engaged position (cf FIGS. 4 and 5),the smallest possible operating force is sought, along with a goodelectrical contact between the moving contacts and the fixed contacts.The out track 56 therefore comprises two parts (for more details seeFIG. 4 in which the parts are hatched): a first part which issubstantially rectilinear 56 a and a second circular part 56 b with asmall radius. In the first part 56 a of the out track 56, the movementof the operating handle of the disconnector 1 generates a proportionaltravel of the moving element 40 and therefore the moving contacts 36. Inthe second part 56 b and starting at the point of equilibrium betweenparts 56 a and 56 b, the movement of the operating handle leads to themoving element 40 moving and closing in quickly, which has the effect ofquickly positioning and squeezing the moving contacts 36 on thecorresponding fixed contacts 33, 33′. The out track 56 presents avariable depth which increases in the direction of rotation and then asudden change of level caused by a shoulder 56 c. Hence, at the end ofthe rotation, the cam 50 moves axially by a value equal to thedifference in depth, slackening the return spring 52. This axialmovement of the cam 50 offers the advantage of positioning the drivefinger 45 immediately in the return track 57.

When the releasing operation takes place, i.e. to go from the engagedposition (cf FIGS. 4 and 5) to the released position (cf FIGS. 2 and 3),what is sought is to achieve the most sudden separation possible betweenthe moving contacts and the fixed contacts. The return track 57therefore comprises two parts (for more details see FIG. 4 in which theparts are hatched): a first circular part 57 a with a constant radiuscentered on the axis A and a second circular part 57 b, the radius ofwhich is much smaller than the constant radius. In the first part 57 aof the return track 57, the movement of the operating handle of thedisconnector 1 has no effect on the movement of the moving element 40and therefore on that of the moving contacts 36. Nevertheless, theenergy is stored in the sudden action device 24. In the second part 57 band starting at the point of equilibrium between the parts 57 a and 57b, the movement of the operating handle, in association with the suddenaction device 24, leads to the moving element 40 and therefore themoving contacts 36 being moved quickly away, resulting in a suddendisconnection. The return track 57 presents a variable depth whichdecreases in the direction of rotation. Hence, during this rotation, thecam 50 moves axially by a value equal to the difference in depth,compressing the return spring 52. This axial movement of the cam 50 hasthe advantage of positioning the drive finger 45 immediately at thestarting point, in the out track 56.

The out track 56 and return track 57 have different reliefs so as toensure that the drive finger 45 is guided properly in the right track sothat it is guided, during the engaging operation, by the inner wall 55 aof the recess and, during the releasing operation, by the outer wall 55b. Furthermore, to avoid too much force being exerted on the drivefingers 45 of the moving elements 40, the axial movement of the cams 50induced by the relief of the out and return tracks, is helped by theadapted cam profile 53 provided on the barrel 51. This cam profile 53rests on the lugs 54 securely fixed to the enclosure 4 and the cap ofthe device 1 and helps the cams 50, in association with the spring 52,to move axially during their rotation.

The out track 56 and return track 57 can present other curves andreliefs so as to optimize the engaging and releasing conditions for eachdisconnector 1.

This disconnector 1 also comprises a test position shown by FIGS. 6 to8. This test position makes it possible to activate auxiliary contactsarranged for example on the control module 2 to test their controlcircuits, making it possible to check the disconnnector's engaged orreleased condition. This test position is obtained by turning the handleof said device at an angle of 60 to 90° in the opposite direction tothat when engaging. During this rotation, the moving elements 40 mustnot move and the disconnector 1 must remain in the released position.Each recess 55 is extended by a test track 58, framed by the inner walls55 a and outer walls 55 b, this track being circular, close to thecontrol shaft 23, with a constant radius and centered on the axis A,ending with a tracking band 59 corresponding to the end of the drivefinger 45 in the test position. On the rear side of the cam 50 acircular groove 60 is provided close to the control shaft 23 andcentered on the axis A. This circular groove 60 is designed to receivethe guide shoe 46 provided on the moving elements 40 facing the drivefinger 45. It makes it possible to ensure the guiding of the movingelements 40 in relation to the cams 50 de so that, when the test phaseis over, the drive finger 45 is positioned again in the right track,i.e. the out track 46.

On FIG. 8, it can be seen that the cam 50 comprises a thinner peripheralzone 61 which serves a double purpose. It first of all allows the cam 50to be mounted in the frame 41 of the moving element 40, between thedrive finger 45 and the guide shoe 46. It then allows the cap (notshown) of the disconnector 1 to be locked automatically when the latteris in the engaged position, by means of an additional device provided onsaid cap.

In the above description, it can be seen that the invention makes itpossible to achieve all the aims mentioned. In conclusion, it makes itpossible to substantially lower the cost of manufacturing thedisconnecting modules and therefore the cost of the disconnector whilstimproving its technical performance. What is more, apart from thecurrent-carrying parts which are made for example of copper, virtuallyall the parts of the drive mechanism of the moving contacts can be madeby molding in a technically suitable material, e.g. thermoplastic orthermoset.

The present invention is not restricted to the example of embodimentdescribed but can be widened to include any modification and alternativewhich is obvious for an expert. Of course, the number of disconnectingmodules depends on the number of phases in the installation with thepresence or not of a neutral conductor. As a result, the number of fixedcontacts, moving contacts, cams, windows and notches provided in theframe of the moving equipment is adapted accordingly. Likewise, theshape of the various parts comprising said control mechanism of themoving contacts can vary whilst remaining within the scope of protectiondefined in the claims. In particular, the layout of the out, return andtest tracks illustrated and described is only given by way of example.

What is claimed is:
 1. Electrical disconnector (1) for a alternating lowvoltage electrical installation provided with at least two phaseconductors with or without neutral conductor, comprising onedisconnecting module (3) per conductor and one joint control module (2)provided with a mechanism for operating said disconnecting modules, eachdisconnecting module comprising at least one input terminal (30)connected to a fixed contact (31), one output terminal (32) connected toa fixed contact (33), another two fixed contacts (31′, 33′) connected toone another by a bridge or a fuse, forming with the other fixed contactstwo pairs of fixed contacts and two moving contacts (35, 36) associatedrespectively with a pair of fixed contacts, the control module (2)comprising at least one control shaft (23) coupled to an operatinghandle, this shaft crossing said disconnecting modules (3) and bearingat least one cam (50) coupled to at least one translation moving element(40) coupled to said moving contacts (35, 36) to move them from a firststable position called the engaged position to a second stable positioncalled the released position, wherein each moving contact (35, 36)comprises two contact surfaces (38) arranged in substantiallyperpendicular planes, and the fixed contacts (31, 31′ and 33, 33′) ofthe same pair are arranged in substantially perpendicular planes so thattheir respective contact surface (37) is placed facing the correspondingcontact surface (38) provided on said moving contact (35, 36) when it isin the engaged position and each moving contact (35, 36) moves in radialtranslation in relation to the control shaft (23) in a substantiallyperpendicular direction (F) to a straight line passing through its twocontact surfaces (38).
 2. Device according to claim 1, wherein eachmoving contact (35, 36) comprises two end arms arranged on either sideof a middle arm forming an angle of approximately 45° in relation tosaid middle arm, the contact surfaces (38) being provided on the two endarms.
 3. Device according to claim 1, wherein the moving element (40) ismade up of a substantially rectangular frame (41) extending through saiddisconnecting modules (3) and arranged in an inclined plane parallel tothe control shaft (23).
 4. Device according to claim 3, wherein theframe (41) comprises at least two parallel sides (47), oriented radiallyin relation to the control shaft (23) and arranged to slide along twocorresponding sides (48) arranged in an enclosure (4) of said device toguide said frame (41) in translation.
 5. Device according to claim 3,wherein the frame (41) comprises for each corresponding moving contact(35, 36) a window (42) oriented substantially perpendicular to thecontrol shaft (23) and a return spring (43) housed in this window (42)to attract said moving contact (35, 36) in the direction of the fixedcontacts (31, 31′ and 33, 33′).
 6. Device according to claim 3, whereinthe frame (41) comprises at least one notch (44) designed to receivesaid cam (50), at least one side of this notch comprising a drive finger(45) substantially parallel to the control shaft (23) and engaged in atleast one track (56, 57) provided in said cam (50).
 7. Device accordingto claim 6, wherein the cam (50) comprises, for each moving element(40), a non circular recess (55), delimited by an inner wall (55 a)close to the control shaft (23) and an outer wall (55 b) at a distancefrom the control shaft (23), these walls being arranged to guide saiddrive finger (45), respectively when engaging and releasing.
 8. Deviceaccording to claim 7, wherein the bottom of the recess (55) comprisesvarious reliefs arranged to define, respectively with the inner walls(55 a) and outer walls (55 b), two distinct tracks (56, 57), i.e. an outtrack (56) for engaging purposes and a return track (57) for releasingpurposes.
 9. Device according to claim 8, wherein the out track (56)comprises a first part (56 a) which is substantially rectilinear and asecond circular part (56 b) with a small radius out-of-center inrelation to the control shaft (23) and the return track (57) comprises afirst circular part (57 a) with a constant radius centered on thecontrol shaft (23) and a second circular part (57 b) the radius of whichis smaller than said constant radius.
 10. Device according to claim 9,wherein the second part (56 b) of the out track (56) communicates withthe first part (57 a) of the return track (57) via a shoulder (56 c).11. Device according to claims 8, wherein the cam (50) comprises acentral barrel (51) rotating securely fixed to the control shaft (23)and sliding on the latter and in that the width of the notch (44)provided in the moving element's frame (41) is greater than that of thecam (50) which allows it an axial clearance (D) corresponding to thedifferences in relief at the bottom of the recess (55).
 12. Deviceaccording to claim 11, wherein on at least one of its free ends, thebarrel (51) has a cam profile (53) co-operating with at least one lug(54) provided at least in the enclosure (4) of said device and orientedradially in relation to the control shaft (23) and in that the controlshaft (23) bears a return spring (52) arranged to keep the cam profile(53) resting on said lug (54).
 13. Device according to claim 8, whereinthe recess (55) is extended, in a direction opposite to that of the outtrack (56) and return track (57), by a test track (58), framed by theinner (55 a) and outer walls (55 b), this track (58) being circular,close to the control shaft (23), with a constant radius centered on thisshaft.
 14. Device according to claim 13, wherein the cam (50) compriseson its rear side a circular groove (60) near the control shaft (23) andcentered on this shaft and the frame (41) of the moving element (40)comprises a guide shoe (46) arranged facing the drive finger (45) andarranged to lodge itself in said groove (60) when the device is in thetest position.